Research On Cascaded H--bridge STATCOM Based On DSP And FPGA

Extra losses of reactive power will not only increase power, may also make the power system voltage instability, and seriously affected makes grid power quality received, sometimes even threatening the normal operation of the power system. Traditional reactive compensation device problems such as slow response times, and reliability is not high, unable to meet compensation demands of modern power systems. Static synchronous compensators(STATCOM) as a new type of dynamic reactive power compensation device with high response speed, adjustable, good reliability, and many other advantages, is the developing direction of reactive power compensation equipment.STATCOM studied cascade h-bridge, have required less switching device, the advantages of easy modular. First an introduction to the main circuit of STATCOM, analyzing a STATCOM works, got control of STATCOM controlling STATCOM output amplitude and phase angle of the voltage on the AC side. Also describes methods of reactive current detection based on instantaneous reactive power theory and reactive current control methods and methods of modulation, PLL.Then cascade h-bridge is derived mathematical model of STATCOM, and analysis of the method of STATCOM DC voltage cascaded h-bridge control, modulation is not a strategy, and balanced working conditions were studied, analyzes the traditional zero-sequence voltage injection method in calculation of zero-sequence voltage faults, simplified calculation method is proposed. This method does not require the traditional current phase-locked loop, with simple mathematical operations can be worked out quickly and need to compensate for zero-sequence voltage, simplified the control algorithms, to a certain extent improve the response speed of the system.Cascade h-bridge was built under MATLAB/Simulink simulation environment simulation model of STATCOM, STATCOM compensating reactive power load balanced and unbalanced reactive loads of static and dynamic characteristic simulation analysis, simulations show that under two conditions of systems by STATCOM can compensate with good results.Also a 10 k V± 1MVar STATCOM prototype introduces the main circuit and control circuit design, and focuses on the main control circuit of the control section, design of signal collection circuit, IGBT drive circuit and protection circuit, single chain link methods and some experimental results are given.